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PENDULUM LEVEL, PLUMB, AND NGLINMETER. No. www.

Patented A9128, 1884.

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Nrren STATES CHARLES J. PARKHURST AND ALBERT W'. PARKHRST, OF .NORTH ADAMS,

Massnonnsn'rrs; SAID ALBERT CHARLES J. PARKHURST.

W. PARKHURST Assrenon- To SAID PENDULUMhLEVEL, PLUMB, AND INCLlNOMETER.

SPECIFICATION forming part of Letters Patent No. 296,608, dated April 8, 1884.

Application filed September 2K8, 1883. (No model.)

To @ZZ whom it may concern): A

Be it known that we, CHARLES J PARK- HURST and ALBERT W. Pnnirnunsir, of -North Adams, county of Berkshire, State of Massa- 5 chusetts, have invented a new and useful Improvementin Pendulum-Levels, of which the following is a full, clear, and exact descrip tion, reference being had to the accompanying drawings, making part of this specification.

Our invention relates to that class of levels, plombs, and inclinometers in which the indexhand is connected with and actuated by means of a pendulum or plumb-bob; and it consists in the combination of the index-hand, the i5 pendulum, and multiplying bevel-gears connecting said hand and pendulum, whereby the sensitiveness of the hand is increased to an extent adapting it to move through an arc of one hundred and eighty degrees, or an entire 2o circle, While the pendulum moves through an arc of ninetyT degrees, relatively, and whereby, also, the shaft of the index-hand is brought into a position at right angles to the pendulum shaft or pivot, as hereinafter explained. 2 5 It further consists in the combination, with the pendulum, of elastic or yielding plates, adapted, at the 1vill of the operator, to grasp and hold the pendulum withthe index-hand at any desired point or angle indicated, and 3o in certain means for adjusting the plates or springs and setting thependulum free, as hereinafter explained.

In the accompanying drawings,

Figure 1 is a perspective View oi our improved level,

plumb, and inclinometer complete. Fig. 2 represents a vertical longitudinal, and Fig. 3 a vertical tranverse, section through the operative parts ofisaid level. Fig. 4 is a perspective view of the Slide and of the swinging end of the crank-arm actuating the Same, for adjusting the spring-plates between `which the pendulum vibrates; and Fig. -5 is an enlarged face view of the dial and index. K

A represents a bar of wood or other suitable material, similar to that employed for the ordinary spirit-level, with its upper and lower sides parallel, and the ends exactly at right angles with the upper and lower sides, and recessed at or near the center of its length on f its upper face; or it may be provided with a mortise, A', extending vertically through it, for convenience in applying the operative parts, hereinafter described, in which case a lacing-plate, B, of metal or other suitable material, may be applied to the lower face of the bar for covering the opening and protecting the operative parts.

C represents a metal pla-te, of a width corresponding to the Width of the bar A, and let into the upper face of said bar, so as to be flush therewith. This plate, at or near the center ofits length, has a circular depression or socket at C', for the accommodation of the dial I) and index-hand e and a glass, f, and its fastening or retaining ring g, for covering and protect` ing said hand, and at the sides of the depression C are pendent lugs or ears cc in suitable bearings, in which the shaft h of the pendulum H is mounted. By preference, the ends of shaft h are made conical and rest in sockets of corresponding form in screw-bearing plugs z, which can be adjusted as required to compensate for Wear, while at the saine time securing ease or freedom of vibration of the pendulum-shaft; but any suitable form of bearings may be employed, and the pendulum may be connected With its shaft in any suitable manner. n

To the shaft h is securedv a bevel-wheel, I, which engages with and actuates a bevel-pinion, I', on a shaft, t'. arranged at right angles With the shaft h, and stepped in a bearing in the horizontal arm c3 of an angular lug or ear, c?, pendent from the plate C. The upper end of the shaft i passes through a central perforation -in the depressed portion C of plate G, and has the index-hand e secured to it. The bevel-gear l is made, by preference, with its circumference equal to four times that of the pinion l in such manner that the movement of the pendulum swinging through an arc of ninety degrees will serve to impart an entire revolution to the pinion I and to the index dial, Whilerepresenting an entire circle, is numbered to indicate ninety degrees, corresponding to the movement of the pendulum relatively to the bar i in the movement of connected with and operated by it, and theA the latter from a horizontal to a vertical posil and'also the glass f, in place, this construction tion, or vice versa, either position being thus indicated by 0 or zero. In some cases it may be found desirable to diminish the movement of the hand to one hundred and eighty degrees in a vibration of the pendulum through ninety degrees, or in that ratio, in which case the circumference of the multiplying bevel -gears connecting said parts will be made two to one instead of four to one, as above described, and as represented in the drawings. The lower bearing of the shafti may be made conical and adjustable, similar to those of shaft h, above described.

To the plate G, near its ends, or to any convenient point, are secured pendent elastic or yielding plates or strips J and J', arranged parallel with each other and with the path of the pendulum, on opposite sides of and in close proximity with the latter. These plates are shown made in the form of strips secured at their ends to the plate C, pendent therefrom, and from the plane of the pendulum-shaft, passing down underneath said shaft each in the form of a semi-annulus or semicircle, of which said shaft is the center, with a radius equal to the length of the pendulum, adapting the latter to swing at all times between them; but the form of the plates may be changed so long as they perform the function hereinafter described. 'Iheyare so placed as, by their elastic pressure, to grasp and firmly hold the pendulum between them, preventing all vibration of the latter. The lower ends of the plates are provided with pendent spurs jj', which rest in clbse proximity with the bottom B ofthe socket A', and in suitable ways at a a in the bar A, or on the bottom plate, B, is mounted a slide, K, provided with a socket or slot, 7c, adapting the swinging end of a crankarm, Z, on a rock-shaft, Ii, to engage with said slide for actuating it.

The end k' of the slide KA is made wedgeshaped, as shown in Fig. 4, and is adapted to be moved by the action of the rock-shaft and its arm between the spurs j and j' for wedging the plates J and J' apart, and so freeing the pendulum and permitting it to vibrate freely,

or to be withdrawn for causing said plates-to grasp and hold said pendulum at any desired point or indication ofthe index-hand.

The shaft K is journaled in the side walls of the socket or mortise A', or in suitable bearing-plates let into said walls, and is provided on one end with a thumb wheel or lever, L', which, by preference, is let into the side of the bar A, so as to be flush on its outer face therewith, and so protected from injury.

In practice we propose to use a magnifying glass or lens for covering the dial D and protectin g the hand e, for a purpose which will be readily understood, and said glass will be secured in place by an elastic band or ring, g, consisting of a closely -wound spiral-spring cord bent into annular form, and compressed so as to snugly fit the side wall of the circular depression in plate C, and thus to hold itself,

facilitating the removal and replacing of the glass; but any other suitable means for securing the glass maybe employed. The plate C, with the operative parts of the level attached to it, may be secured in the bar A in any suitable manner, screws being shown in the drawings for the purpose. Other means-such, for instance, as cams or toggle-levers-may be employed for wedging the plates J and J apart and freeing the pendulum, if desired, without departing from our invention; but those described are preferred.

By the construction described the instrument is adapted to serve not only as a level,

but also to indicate any degree or angle of vav riation therefrom up to ninety degrees or more, and thus to serve also as a plumb or inclinometer, and by the arrangement whereby the pendulum may be locked and held at any point indicated byl the instrument, the necessity for otherwise recording such indications may frequently be avoided.

In instruments of the kind described, where great accuracy is desired, the chamber A', in which the operative parts are located, may in practice be made air-tight, and the air may be substantially exhausted therefrom by any suitable means, thereby to a great extent avoiding the frictional resistance of the air to the movement ofthe pendulum and gears, and rendering the instrument extremely sensitive.

The instrument may of course be ornamentally nished, if desired, in a manner common with this class of instruments, and according to the fancy of the manufacturer or user.

I- Iaving now described our invention, what we claim as new is, viz:

I. In apendulum-level, plumb, or inclinometer, the shaft or pivot of the index-hand conioo nected with the pendulum shaft or pivot by multiplying bevel-gears, for the purpose and substantially as described.

2. In a pendulum-level, the combination of the index-hand, the pendulum, and multiplying bevel-gears connecting said pendulum and index-hand, and adapting said index-hand to be moved over a greater distance than the pendulum, substantially as described.

3.- In a pendulum-level, the pendulum and the index-hand arranged on axes at right angles one with the other, and combined substantially as described, whereby the indexhand is made to move through an entire circle in the movement of the pendulum through an arc of ninety degrees.

4. Ina pendulum-level, plumb, or inclinometer, the pendulum suspended between elastic plates or springs adapted to grasp and hold said pendulum at any desired point.

5. The pendulum actuating the index-hand, pivoted 'between elastic plates or frames adapted to hold said pendulum in any desired position, in combination with means for forcing said plates apart and freeing the pendulum, substantially as described.

6. In a pendulum-level, plumb, or inclinom- IIO eter, the pendulum'supported between yielding side plates, in combination with the slide for separating said plates, and the thumb shaft and lever for` operating wid slide, substantially as described.

7. The combination, in u pendulum-level, i

plumb, or inolinometer, of the pendulum, the index-hand with its pivot at right angles to the pendulumshaft and geared. thereto, the elastic plates or springs for holding said pendnlum at any desired point, and means for adjusting said plates, all substantially as described;

In testimony whereof We have hereunto set our hands this 22d day of September, A. D. 15 1883. Y

CHARLES J. PARKHURST. ALBERT W. PABKHURST.

lVtnesses; l

ARNOLD G. POTTER, WARREN H. BIXnY. 

